I received the data logger and have been trying it out.
I think this is a very sensitive instrument. Almost all the displays keep changing even though the device isn't moving. Is that normal?
For example, the speed indicator always keeps changing, even though it is sitting stationary on the desk. Is this normal? Can I calibrate it to read 0.0 m/s when it isn't moving? If so, how? Or is that just the error inherent in the system? In that it is constantly changing, it isn't possible to just offset it when doing my analysis.
Most of the readings do that. I have attached a 3 minute recording of the instrument sitting undisturbed on my desk - not moving, not bumped, nothing. Is this variation in reading normal?

Yes the unit indeed is very sensitive and that is exactly as it should work: Our GPS logger offers the real RAW sensor data without any tricks.
You can simply remove the “noise” by AVERAGING the data. This is the regular post processing most of our users do. Then you get a very stable readout with almost zero for all sensors (if the unit is not moving e.g. "just sitting on the desk"). But please note that even the slightest vibration will result in a rise of data change (e.g. your PC fan under the desk).

Attached a sample of you data (grey is original and green is a simple 1:5 averaging). As you can see you almost get a flat line but the first 2 "bumps" for sure are real very slight movements/vibration. If you rise the averaging to 1:10 or 1:30 it will even get better.